WORK CABINET

Abstract: Cabinet acting as a fume cupboard and, alternatively, as a work bench, comprising a cabinet hood (3) having associated sidewalls (4), a rear wall (25), a front having an access opening (7) and a slide door (9), and a work bench (19) having a perforation (23) and a suction tray (21), and a ventilation duct (39) for connection to a suction fan, characterized by a suction box (33) arranged in the upper part of the cabinet hood (3) said box being in connection with the ventilation duct (39) and occupying depthwise only part of the upper end of the cabinet which is otherwise open, said box at the lower part thereof being connectable with the interior of the cabinet hood, furthermore characterized by ducts (29, 31) which connect the area above the perforation or the suction tray (21) to the suction box (33), and by an adjustment damper (41) which is adjustable between a first position (L1) that essentially blocks the connection between the suction box (33) and the interior of the cabinet hood (3), and a second position (L2) that essentially blocks the connection between the interior of the cabinet hood (3) and the surroundings, whereby the cabinet mainly operates as a fume cupboard.

Description: WORK CABINET The present invention relates to a cabinet acting as a fume cupboard, alternatively as a work bench. In a con- ventional manner the cabinet comprises a cabinet hood having side walls, a rear wall and a front with an access opening and a slide door, and ventilation means to* create subpressure in the cabinet or the work bench. In laboratory interiors, where work with toxic chemi- cals takes place, there are found as a standard on the one hand fume cupboards of a conventional type, and on the other hand so called work benches. In a work bench work is performed with dangerous chemcials, for example substances releasing toxic or corrosive vapours or the like, and the work in fume cupboards is often associated with heating, the ventilation through an underpressure in the cabinet taking place with the creation of an upwardly directed air flow. This means that in a fume cupboard of a conventional type the ventilation air in principle leaves at the upper part of the cabinet. However, in so called work benches the ventilation takes place downwardly through a perforated work plate, so called perforature, and in such work bench there is usual¬ ly performed work taking place without warming or heating. Thus, this type of ventilation takes place through venti¬ lation down through a perforated work support, the perfo¬ rature being thus supported on some sort of suction tray, wherein a vacuum is generated for the purpose of removing dangerous gases so that these will not come into contact with the laboratory operator. In conventional techniques the equipment is designed in such a manner that the fume cupboards are arranged separate from the work benches which results in extensive space requirements and therefore means that the equipment requires extensive space and, furthermore, the physical separation between fume cupboards and work benches results in impaired installation flexibility. The present invention has for its main purpose to provide a modified work cabinet which can be alternatively used as a fume cupboard or as a work bench, this being possible by a simple adjustment procedure within the frame work of the same construction. Another purpose of the invention is to provide a work cabinet which results in improved flexibility in connec¬ tion with ventilation dynamics and enables a generally improved ventilation. Yet another object of the invention is to provide a work cabinet which, in spite of its simple construction, functions well, as a fume cupboard as well as a work bench without setting aside the safety for the laboratory ope¬ rator. For these and other objects which will be clear from the following disclosure there is provided through the invention a cabinet acting as a fume cupboard and, alter¬ natively, as a work bench. The work cabinet according to the invention comprises a cabinet hood having associated side walls, a double rear wall, a front having an access opening and a slide door, and a work bench having a per¬ forature and a ventilation duct for connection to a suc¬ tion fan or other means capable of generating subpressure in the cabinet. The cabinet according to the invention is characte¬ rized by a suction box arranged in the upper part of the cabinet hood, said box being in connection with the ven¬ tilation duct and occupying depthwise only part of the upper end of the cabinet which is otherwise open, said box at the lower part thereof being connectable with the in¬ terior of the cabinet hood. Furthermore, the cabinet is characterized by ducts which connect the area above the perforature or the suction tray to the suction, box, and by an adjustment damper which is adjustable between a first position that essentially blocks the connection between the suction box and the interior of the cabinet hood, and a second position that essentially blocks the connection between the interior of the cabinet hood and the surroundings, whereby the cabinet mainly operates as a fume cupboard. It is preferred that said ducts are arranged adjacent to the rear wall of the cabinet and, optionally, also in association with the side walls of the cabinet. It is particularly preferred that at least a first duct is arranged adjacent to the rear wall and that at the lower end thereof it is connected to the suction tray for down- ward suction through the perforature. It is also particularly preferred that at least a second duct is arranged adjacent to each of the side walls and adjacent to the rear wall on each side of said first duct. These second ducts open at the lower end thereof into the area above the perforature for suction backwardly across said perforature. In a particularly preferred embodiment of the cabinet according to the present invention said first duct which is connected to the suction tray is flanked by said second ducts opening into the area above the perforator, said ducts thus being arranged adjacent to the rear wall 25. In a preferred embodiment of the cabinet according to the invention said suction box is provided with a down¬ wardly oriented wall thus separating at its upper end the suction box area from the other part of the cabinet. The damper is preferably pivotably arranged at the lower edge of the downwardly oriented wall. In order to enable con¬ trol of the dynamic charcteristics of the ventilation system it is preferred that the connection between the suction box and the interior of the cabinet contains a restriction element or grid, whereby the flow resistance through said connection can be controlled. It is suitable to arrange a drive motor, particularly an electric one, by means of which the damper can be moved between the two positions for changing the cabinet to a fume cupboard or to a work bench. In a manner known per se the slide door may be con¬ nected to a counter weight, for example via cords running over pulleys, whereby its displacement upwardly is facili¬ tated by balancing the weight of the slide door. In order to facilitate work in the cabinet according to the invention a lamp mounting is suitably placed on the front of the cabinet above the working position. Accordingly, the cabinet according to the present in¬ vention is at its upper part provided with a suction box extending essentially across the full width of the cabinet and suitably being positioned adjacent to the rear wall of the cabinet. The adjustable damper means that the venti¬ lation characteristics of the cabinet can be changed between on the one hand the use of the cabinet as a fume cupboard and on the other hand for use as a work bench. In between intermediate positions can be used as desired de¬ pendent on the type of work performed in the cabinet. However, normally the cabinet according to the invention either operates as a fume cupboard or as a work bench. In the following the invention will be illustrated further by the description of a preferred embodiment of the cabinet according to the invention. However, the in¬ vention is not restricted to this description of a pre¬ ferred embodiment. Said embodiment is presented in the following disclosure made in association with the appended drawings, wherein: Fig. 1 shows diagrammatically a front view of a cabinet designed in accordance with the invention; Fig. 2 shows a side view of the cabinet according to Fig. 1; and Fig. 3 shows a plan view in a section along line A-A in Fig. 2.. The work cabinet shown in the drawings and generally designated 1 comprises, in a conventional manner, a cabinet hood 3 provided with side walls 4 and a rear wall 25. The front of the cabinet is provided with an access opening 7 with an associated slide door 9 which, by means of a handle 11, can be moved upwardly or downwardly to a suitable access opening, the position shown in Fig. 2. In order to facilitate the anoevering of the slide door the cabinet is provided with a counter weight 17 which, via cords 13, is connected to the upper part of the slide door 9. In order to facilitate vertical movement of the slide door 9 said cords 13 travel over pulleys 15 arranged at the upper part of the cabinet. In said upward movement the slide door 9 moves in a space inside the front of the cabinet defined by a downwardly directed wall section 18 at the upper end of the cabinet. In the embodiment shown the cabinet 1 rests on four legs 5 for providing suitable working level. However, the cabinet can, of course, be anchored directly against the wall in a laboratory space without the use of legs. At a suitble working level a work surface or work bench 19 is arranged which is provided with a perforated sheet 23 having openings 24 and a suction tray 21 arranged under the perforated sheet or perforature. Furthermore, there is arranged on one side of the cabinet in a conven¬ tional manner a discharge funnel 20 and discharge means 22 for water, gas etc. In association with the rear wall 25, which is double so as to create a space 27 for the counter weight 17, two side ducts 29 and one central duct 31 are arranged. In association with the upper part of the rear wall 25 a suction box 33 is arranged which is provided with a front wall 35, and via a perforated grid 37 the suction box 33 is in communication with the interior of the cabinet. Furthermore, suction box 33 is provided with a ventilation duct 39 for connection to a suction fan not shown for pro¬ viding subpressure in the cabinet and thereby the desired ventilation. The central duct 31 opens at its upper end into the suction box 33, whereas at its lower end it is in connec¬ tion with the suction tray 21 for a purpose to be de¬ scribed below. The flanking side ducts 29 are also at their upper ends in connection with the suction box 33 but open at their lower ends in the area above the perforature 23, also here for a purpose to be described below. Along the front wall 35 of the suction box 33 a ma- nually or motor-operated adjustment damper 41 is provided which can be pivoted between the extreme positions indi¬ cated L. and L- in Fig. 2. This adjustment damper 41 can be controlled manually or via an electric motor 43 dia- grammatically shown in Fig. 1. The motor 43 is operated from the control panel 40 by means of control means 45 and 47, actuating control member 47 bringing damper 41 to position L. , whereas actuating control member 45 bringing damper 41 to position L-. The function of the cabinet described is briefly the following. It is assumed that cabinet 1 shall be used for working with substances which require heating where poisonous vapours are generated. In other words, the ca¬ binet in this case shall function as a fume cupboard. By means of pressing knob 45 damper 41 is moved to the position shown by L 2 in Fig. 2 by means of the driving motor 43. This will cause essential blockage of the direct connection between the interior of the cabinet and the surrounding via the otherwise open upper end. Wit damper 41 in this position there is thus established con- nection between the suction box 33 and the interior of th cabinet via the perforated grid 37, and ventilation is maintained in the cabinet by an upwardly directed air flo as in a normally operating fume cupboard. In a closed con dition about 50% of the ventilation air leaves by a passage through the perforated grid, whereas the reminder passes via ducts 29 over the perforature 23 and a minor part also through the central duct 31 through the per¬ forature 23. When work of work bench nature shall be carried out, which normally takes place without heating of the chemi¬ cals involved, the damper 41 is adjusted to the position shown by L 1 in Fig. 2 by pressing knob 47. Under these conditions the cabinet according to the invention operates as a work bench in that the connection between the inte¬ rior of the cabinet and the surrounding via the partially open upper part of the cabinet results in downwardly di- rected ventilation in the cabinet, where the major part of the air passes down through perforature 23 and up through the cental duct 31, whereas a minor part, for example about 30%, of the ventilation air passes out through side ducts 29, the remaining about 10% passing out through suction tray 33 by leakage around damper 41. From the above description it is thus clear that by simple switching it is possible to change the cabinet function from normal fume cupboard function to work bench function, which means that the space requirement in a certain laboratory can be substantially reduced since fume cupboards and work benches need not be directed as sepa¬ rate working positions. With regard to the cabinet construction in other respects the materials are conventional and the cabinet frame work can be made for example using a particle board and a white laminate, whereas the slide door can be made of a safety laminate glass and the work bench made with a perforature of acid-proof stainless steel. The work surface may, of course, also be made from any resistant polymer, such as polypropylene, or from enamel or ceramic or an epoxi material. The instrument panel 40 placed at one side of the cabinet results in ease of survey and simple operation, and installation connections involved can take place both from floor or from roof or both. Even if the invention has been described in con¬ nection with a specific preferred embodiment the invention is in no way restricted to this with regard to construc¬ tional details or function in other respects. The skilled artisan easily realizes how modifications and changes can be made within the scope of the appended patent claims.

Claims: δ CLAIMS 1. Cabinet acting as a fume cupboard and, alterna¬ tively, as a work bench, comprising a cabinet hood (3) having associated εidewalls (4), a rear wall (25), a front having an access opening (7) and a slide door (9), and a work bench (19) having a perforature (23) and an suction tray (21), and a ventilation duct (39) for connection to a suction fan, characterized by a suction box (33) arranged in the upper part of the cabinet hood (3) said box being in connection with the ventilation duct (39) and occupying depthwiεe only part of the upper end of the cabinet which is otherwise open, said box at the lower part thereof being connectable with the interior of the cabinet hood, furthermore characterized by ducts (29,31) which connect the area above the perforature or the suction tray (21) to the suction box (33), and by an adjustment damper (41) which is adjustable between a first position (L,) that essentially blocks the connection between the suction box (33) and the interior of the cabinet hood (3), and a second position (L 2 ) that essentially blocks the con¬ nection between the interior of the cabinet hood (3) and the surroundings, whereby the cabinet mainly operates as a fume cupboard. 2. A cabinet according to claim 1, characterized in that said ducts (29,31) are arranged adjacent to the rear wall (25) of the cabinet (1) and, optionally, also in association with the side walls (4) of the cabinet (1). 3. A cabinet according to claim 2, characterized in that at leaεt_ a first duct (31) is arranged adjacent to the rear wall (25) and connected, at the lower end there¬ of, to a suction tray (21) for evacuation downwardly through the perforature (23). 4. A cabinet according to claim 3, characterized by at least a second duct (29) arranged adjacent to each of side walls (4) and adjacent to the rear wall (25) on each side of said first duct (31), said other ducts (29) ope- ning at the lower end thereof in the area above the perforature (23) for suction rearwardly above same. 5. A cabinet according to claim 4, characterized in that said first duct (31) is flanked by said other ducts (29). 6. A cabinet according to any preceding claim, cha¬ racterized in that said adjustment damper (41) is pivot- ably arranged at the lower edge of the downwardly exten¬ ding wall (35) belonging to suction box (33). 7. A cabinet according to any preceding claim, cha¬ racterized in that the connection between suction box (33) and the interior of cabinet (1) contains a restricting element or grid (37), whereby the flow resistance through said connection can be controlled. 8. A cabinet according to claim 6 or 7, characterized by a drive motor (43), by means of which the damper can be moved between the two positions (L. ; L,). 9. A cabinet according to any preceding claim, cha¬ racterized in that said slide door (9) is connected to a counterweight (17) in order to facilitate its upward move¬ ment. 10. A cabinet according to any " preceding claim, cha¬ racterized by a lamp mounting (12) positioned on the front of cabinet (1) above working position.

Inventors: HENNINGSON CLAES, HENNINGSON, CLAES
Applicants: HENNINGSON CLAES, HENNINGSON, CLAES
Application year: 1994
Main classification: B08B15
IPC codes: B08B15